A right triangle. This is the proof of the Pythagorean Theorem supposedly written by Pythagoras about 500 BC: The Pythagorean Theorem says that in a right triangle, the sum of the squares of the two right-angle [...]
Early modern science: Tycho Brahe (He looks funny because his nose got cut off in a duel and he wore a false one made of brass.) New observatories in Europe [...]
René Descartes Who was Descartes? René Descartes was one of the earliest philosophers of the European Enlightenment, in the early 1600s AD. He was just 8 years younger than Hobbes. While Descartes [...]
Medieval science: an Italian pharmacy jar, about 1400 AD (Metropolitan Museum, New York) Learning from Islamic science During the Middle Ages, the best scientists and doctors weren't in Europe. They were [...]
A number line is infinite in both directions. Numbers are a convenient way for people to organize their thoughts about space and time. First we can think of zero as a point, taking up no [...]
Calculating the area of your room. The area of a room is the size of the floor. Suppose you wanted to find out whether your room was really bigger than [...]
This is an equilateral triangle. A triangle is any set of three points on a plane and the lines connecting those points to each other, as long as the three points aren't all on the [...]
This is a trapezoid. A trapezoid is a kind of quadrilateral that has at least two sides that are parallel to each other. A parallelogram is a trapezoid that has two pairs of parallel [...]
This is a square. The darker purple line is the perimeter of the square. A square is a flat shape, in one plane, defined by four points at the four corners. A square [...]
This is a sphere. A sphere is a three-dimensional circle. Or you could say that a sphere is the set of all the points that are at the same distance from the center [...]
